How can i get the x value for a chosen y value?

I've plot my spectrum with "plot (abs(wave));". I successfully got my Y max value with "maxY = max(abs(wave))". But now I want the X axis value that corresponds to my maximum Y value. Anybody can help? Thank you in advance!

Answer 1

[Iain]

 [maxY index] = max(abs(wave));

index is either the X value, or something you can use to get the x values, eg,

 x = 1:54:23423 
 correspondingX = x(index);

[nevin]

This was very helpful. Thank you so much my kind sir!